QoS killing my 'Exempt' PC performance.. but why?

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Pizzimperfect
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Joined: 13 Jun 2013
Posts: 56

PostPosted: Sat Nov 09, 2013 23:45    Post subject: QoS killing my 'Exempt' PC performance.. but why? Reply with quote
Hi all,

I've set up QoS on my E4200v1 running DD-WRT v24-sp2 (03/25/13) big - build 21061

There are 4 devices in the house which use my 100mbps connection.

I ran a speed test and got..



So therefore I have my basic config (-10% of the full connection as suggested from what i've read) set as:



I've set my main PC as 'Exempt' via its static IP address, however now with QoS enabled i'm getting...



Currently there's nobody else here using the network at all, so I figure I should be getting the full throughput?

Can anybody shine any light on this for me?
For reference, here's the full QoS page...



Thanks in advance!
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Pizzimperfect
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Joined: 13 Jun 2013
Posts: 56

PostPosted: Sun Nov 10, 2013 15:02    Post subject: Reply with quote
Just to check, I also tried changing my PC to 'Premium' QoS, same result.
<Kong>
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Joined: 15 Dec 2010
Posts: 4354
Location: Germany

PostPosted: Sun Nov 10, 2013 15:43    Post subject: Reply with quote
QOS needs a lot of CPU power your router is simply to weak to do QOS on a 100Mbps line, you need something faster e.g. a dual core arm router.
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Pizzimperfect
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Joined: 13 Jun 2013
Posts: 56

PostPosted: Sun Nov 10, 2013 15:46    Post subject: Reply with quote
Kong,

Thanks for your reply. That's a shame, I really need a way of limiting one particular person in the house from using an insane amount of bandwidth. Are there any alternatives? Besides murder...

Thanks
Pizzimperfect
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Joined: 13 Jun 2013
Posts: 56

PostPosted: Sun Nov 10, 2013 18:43    Post subject: Reply with quote
I've just been reading that Tomato handles QoS well, would I run into the same problem even with that?
<Kong>
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Joined: 15 Dec 2010
Posts: 4354
Location: Germany

PostPosted: Sun Nov 10, 2013 19:42    Post subject: Reply with quote
Pizzimperfect wrote:
I've just been reading that Tomato handles QoS well, would I run into the same problem even with that?


If you use a newer dd-wrt build you are probably able to get a few more Mbps out of your line, since I fixed a couple of performance brakes in builds around 22000. At least the latest dd-wrt builds are as fast as tomato builds that don't use any special hack or ctf, which will break your qos setup anyways, so yes I don't think there is any build for that unit, that can handle 100Mbps once QOS is used.

You can try one of my 22200 builds:

http://www.desipro.de/ddwrt/K26/

The Readme will tell you which build you need

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Pizzimperfect
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Joined: 13 Jun 2013
Posts: 56

PostPosted: Mon Nov 11, 2013 15:11    Post subject: Reply with quote
Bah! I wish I had known that before I bought the router :\

Nevermind, I'll no doubt be making the jump to AC in the next few months anyway.

Thanks!
Pizzimperfect
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Joined: 13 Jun 2013
Posts: 56

PostPosted: Mon Nov 11, 2013 19:43    Post subject: Reply with quote
Just thought this may be worth mentioning, my CPU load when QoS is on and i'm trying to get those higher speeds is only around 25% ...

Just in case this indicates the issue could be elsewhere

Thanks
<Kong>
DD-WRT Guru


Joined: 15 Dec 2010
Posts: 4354
Location: Germany

PostPosted: Mon Nov 11, 2013 19:45    Post subject: Reply with quote
Pizzimperfect wrote:
Just thought this may be worth mentioning, my CPU load when QoS is on and i'm trying to get those higher speeds is only around 25% ...

Just in case this indicates the issue could be elsewhere

Thanks


And did you look at the sirq value:-)

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Pizzimperfect
DD-WRT User


Joined: 13 Jun 2013
Posts: 56

PostPosted: Mon Nov 11, 2013 19:47    Post subject: Reply with quote
Sirq value...?

I just found it under Status Razz

Sorry if it's a stupid question but where do I find the sirq value...

Thanks Kong! I am trying to spread the knowledge on the board too and not just take it and run Smile
phuzi0n
DD-WRT Guru


Joined: 10 Oct 2006
Posts: 10143

PostPosted: Wed Nov 13, 2013 21:54    Post subject: Reply with quote
Telnet/ssh to the router and run the "top" command. Soft interrupts will be killing your cpu.

The easiest solution is to get a cheap old used router and connect that person through it. Those old G spec models can only handle 30-40mbps without even running QoS.

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slice1900
DD-WRT User


Joined: 18 Feb 2013
Posts: 99

PostPosted: Wed Nov 13, 2013 23:33    Post subject: Reply with quote
Would there be any way other than using QoS to do what OP is trying to do, to give one IP (or in my case one subnet) absolute preference over everything else?

QoS really seems like overkill for a "give this absolute priority over everything else" case, is there perhaps a way to accomplish this via iptables or something else that doesn't require QoS?

In my case QoS would be a real problem to implement, because my DD-WRT router shares the WAN with a firewall device required for PCI compliance. The restriction that QoS has to be told how much bandwidth is available is kind of a problem because I don't know how much bandwidth there is due to the fact it isn't all going through the DD-WRT router. Most of the time the DD-WRT router would have access to all of it, but at certain (unscheduled) times the firewall device (and the devices behind it) will be hitting the WAN fairly hard.
archon123
DD-WRT Novice


Joined: 05 Dec 2013
Posts: 1

PostPosted: Thu Dec 05, 2013 10:28    Post subject: solution maybe?` Reply with quote
1. limit qos on the original subnet/vlan to what you think will slow them down.

2. Create a new ssid on a different subnet/vlan

3. join your new ssid subnet/vlan without qos.



wouldn't this work?
MongooseProXC
DD-WRT User


Joined: 24 May 2012
Posts: 235

PostPosted: Thu Dec 05, 2013 18:32    Post subject: Re: QoS killing my 'Exempt' PC performance.. but why? Reply with quote
Pizzimperfect wrote:
Hi all,

I've set up QoS on my E4200v1 running DD-WRT v24-sp2 (03/25/13) big - build 21061

There are 4 devices in the house which use my 100mbps connection.

I ran a speed test and got..



So therefore I have my basic config (-10% of the full connection as suggested from what i've read) set as:



I've set my main PC as 'Exempt' via its static IP address, however now with QoS enabled i'm getting...



Currently there's nobody else here using the network at all, so I figure I should be getting the full throughput?

Can anybody shine any light on this for me?
For reference, here's the full QoS page...



Thanks in advance!


Use an older build along with HTB packet scheduler to get a truly exempt QOS. I believe the handling of that class was changed around build 20801 so try a build under 20000.
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